The use of digital video has grown dramatically in recent times. Digital video applications include video-conferencing, video-on-demand, digital television, digital cinema, distance learning, entertainment, surveillance, advertising and many more. One of the popular applications of digital video is watching movie clips recorded on a digital video disc (DVD), a blu-ray disc or downloaded over the Internet. The proliferation of digital video into more applications is encouraged by improving compression technology, better authoring and editing tools, cost effective capture and display devices, and economically available bandwidth in digital communication networks.
Digitalization of video offers many advantages for processing and distributing video and other types of information. For example, an unlimited number of copies can be produced from a single digital video signal. While the aforementioned advantage offer immense opportunities for the creators of the video to reach out to their target audiences and consumers, the ability to make copies and the ease by which those copies can be distributed also facilitate misuse, illegal copying and distribution, usually referred to as piracy, plagiarism, and misappropriation.
The processing of digital video has given rise to various techniques, such as shot detection, also referred to as shot boundary detection; feature extraction, and video synchronization. In video processing, a shot refers to a continuous strip of motion picture film, comprising a series of frames that may run for a definite time period. The shots are generally filmed with a single camera and can be of any duration. Shot detection is the automated detection of transitions between shots in the digital video, generally for the purpose of temporal segmentation of videos. Thus shot detection techniques are used to break up a video file into temporal units, i.e. the shots. Shot detection techniques are generally used for automated indexing, content-based video retrieval, and in summarization applications which provide an efficient access to large video files. The techniques of shot detection are generally based on the transition effects between the shots. Conventionally used transition effects include hard cuts, wherein there is an instantaneous transition from one shot to the next; fades, wherein there is A fade is a gradual transition between a shot and a constant image (fade-out) or between a constant image and a shot (fade-in); dissolve, wherein there is a gradual transition from one shot to another, in which the first shot fades out and the second scene shot fades in; and wipe, in a line moves across the screen, with the new shot appearing behind the line.
Another frequently used technique in video processing is feature extraction. In feature extraction, algorithms are used to detect and isolate various desired portions or shapes or contours or histograms, collectively referred to as features, of a digital video. The feature extraction techniques usually involve various image processing techniques, such as edge detection, corner detection, blob detection, ridge detection, and scale-invariant feature transform.